SORT BY:

LIST ORDER
THREAD
AUTHOR
SUBJECT


SEARCH

IPS HOME


    [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

    Re: iSCSI draft-07 Padding



    Michael Schoberg wrote:
    
    > I couldn't find anything in the latest iSCSI spec (draft-07) that prevents
    > someone from issuing multiple padded PDU's for iSCSI Data In/Out segments.
    > I guess I'm worried that someone could issue padded odd-length write/read
    > data when it wasn't necessary.  Example: When moving a 512 byte disk sector
    > an initiator/target could legally issue 512 1-byte DataSegmentLength
    > messages (each padded up to a 32-bit boundary).  This isn't the sort of data
    > stream one would expect, but it's allowed in the draft.
    
    Michael,
    
    I think that the performance will be so poor that it will bury the vendor
    before
    he had time to sell anything.
    
    >
    >
    > This also leads into whether fixed or minimum length data segments (for all
    > but the last) would be nice to include as part of the spec.  It may result
    > in a simpler software/hardware design.
    
    I don't like this idea. The protocol must have the flexibility to work with
    PDUs
    as small as needed to put one PDU per TCP segment.
    This will help a lot the hardware to deal with out of order or missing TCP
    segments
    at high rates.
    If we don't have this possibility we need to rely on an intermediate chuncking
    protocol that we don't have now, or on the markers but they moved as an annex.
    Hence to preserve all our chances to have a protocol that flies at 10G i would
    not
    put this minimum size limitation.
    
    Regards,
    
    Pierre
    
    
    


Home

Last updated: Tue Sep 04 01:04:15 2001
6315 messages in chronological order